A level Biology: Post your doubts here!

[Tasneeem]

Can anyone please explain me the process of phagocytosis?

The process of phagocytosis:
1. In the tissues attacked by pathogens mast cells produce histamine which causes inflammation and attract neutrophils.
2. Iflammation means that blood vessels dilate so more blood reaches site of attack and making capillaries leaky so phagocytes can ne squeezed out.
3. Neutrophils attracted towards the antigens by chemotaxis
4. Bacteria may be attracted directly to the membrane of neutrophil or marked by an antibody or plasma protein as the surface of neutrophil contains receptors for antibodies and plasma protein where they can be fiitted to stimulate the process of phagocytosis. (plasma protein used in marking antigen in known as complement or opsonin protein)
5. Pathogen is engulfed and taken in a vesicle by endocytosis.
6. Lysosomes fuse with the phagocytotic vesicle where bacteria are killed by free radicals, H2O2 and digested by enzymes.

 

[Bba321]

The process of phagocytosis:
1. In the tissues attacked by pathogens mast cells produce histamine which causes inflammation and attract neutrophils.
2. Iflammation means that blood vessels dilate so more blood reaches site of attack and making capillaries leaky so phagocytes can ne squeezed out.
3. Neutrophils attracted towards the antigens by chemotaxis
4. Bacteria may be attracted directly to the membrane of neutrophil or marked by an antibody or plasma protein as the surface of neutrophil contains receptors for antibodies and plasma protein where they can be fiitted to stimulate the process of phagocytosis. (plasma protein used in marking antigen in known as complement or opsonin protein)
5. Pathogen is engulfed and taken in a vesicle by endocytosis.
6. Lysosomes fuse with the phagocytotic vesicle where bacteria are killed by free radicals, H2O2 and digested by enzymes.

The process of phagocytosis:

Thankssss Tasneem
Can you also tell me if we have to write about macrophages and all in this?

 

[Tasneeem]

No because macrophages have their role as an antigen presenting cell (APC)
Macrophage engulfs pathogen and then expose its antigens on its surface to stimulate immune system to be prepared to attack this type of antigen. This process known as antigen presentation.

 

[Bba321]

Thanks hope you

No because macrophages have their role as an antigen presenting cell (APC)
Macrophage engulfs pathogen and then expose its antigens on its surface to stimulate immune system to be prepared to attack this type of antigen. This process known as antigen presentation.

thanks hope you get As and A*s

 

[Tasneeem]

Thanks hope you

thanks hope you get As and A*s

no need you too sweetie

 

[shaminou]

What about biology practical?? When do you have p34?

 

[shaminou]

The process of phagocytosis:
1. In the tissues attacked by pathogens mast cells produce histamine which causes inflammation and attract neutrophils.
2. Iflammation means that blood vessels dilate so more blood reaches site of attack and making capillaries leaky so phagocytes can ne squeezed out.
3. Neutrophils attracted towards the antigens by chemotaxis
4. Bacteria may be attracted directly to the membrane of neutrophil or marked by an antibody or plasma protein as the surface of neutrophil contains receptors for antibodies and plasma protein where they can be fiitted to stimulate the process of phagocytosis. (plasma protein used in marking antigen in known as complement or opsonin protein)
5. Pathogen is engulfed and taken in a vesicle by endocytosis.
6. Lysosomes fuse with the phagocytotic vesicle where bacteria are killed by free radicals, H2O2 and digested by enzymes.

Is it also found in AS biology??

 

[Tasneeem]

What about biology practical?? When do you have p34?

We did it last tuesday !

 

[Tasneeem]

Is it also found in AS biology??

yeah this is in AS biology about immunity

 

[shaminou]

We did it last tuesday !

How was it??

 

[shaminou]

yeah this is in AS biology about immunity

Thanks a whole lot.
Can you tell me how to measure cell diameter with an eyepiece graticule please??

 

[Tasneeem]

How was it??

It was kinda easy Thanks god there were no eyepiece graticule

 

[shaminou]

It was kinda easy Thanks god there were no eyepiece graticule

Got lucky. ^_^

 

[Tasneeem]

Thanks a whole lot.
Can you tell me how to measure cell diameter with an eyepiece graticule please??

you have to caliberate first the eye piece graticule to determine the size of the graticule unit in mm or um
then remove the stage micrometer and put the slide to determine its size in graticule units
then cross multiplication
Ex. if 100 eye piece graticule divisions measures 0.25mm, therefore each graticule unit equal to 0.25mm divided by 100=2.5um

 

[shaminou]

you have to caliberate first the eye piece graticule to determine the size of the graticule unit in mm or um
then remove the stage micrometer and put the slide to determine its size in graticule units
then cross multiplication
Ex. if 100 eye piece graticule divisions measures 0.25mm, therefore each graticule unit equal to 0.25mm divided by 100=2.5um

With what apparatus shall you determine the size of eyepiece graticule??

 

[Tasneeem]

With what apparatus shall you determine the size of eyepiece graticule??

Stage micrometer !

 

[shaminou]

Stage micrometer !

Thank you very much dear. Do you have a video or a link regarding practical biology? Especially microscopy.

 

[Tasneeem]

Thank you very much dear. Do you have a video or a link regarding practical biology? Especially microscopy.

No need <3
Nope sorry

 

[shaminou]

No need <3
Nope sorry

It's ok dear. Thanks a lot. Do you have some advice to give me for practical biology??

 

[Tasneeem]

It's ok dear. Thanks a lot. Do you have some advice to give me for practical biology??

Manage your time!
Revise the structures of the plant and how to draw a plan diagram
Beside each label put a small note
and good luck